Various types of wireless networks that utilize channels in frequency spectrum that is shared with other networks have been proposed. The sharing of frequency spectrum allows a wireless network to increase system bandwidth efficiency when channels in the shared frequency spectrum are available for use by the wireless network. In various configurations of these networks, the shared frequency spectrum may be spectrum in unlicensed frequency bands or spectrum in licensed or allocated frequency bands that are shared between licensed networks, for example, on a prioritization basis. The prioritization may be implemented on a tier level basis, in which different levels of priority for use of the frequency spectrum are assigned to different networks. These networks may include networks configured for use with different market segments. For example, the networks that share frequency spectrum may each be configured for Department of Defense (DOD) users, police department users, or cellular users. The networks may also be configured for the same market segment. For example, the networks that share frequency spectrum may each be configured as a corporate network.
An example of networks utilizing shared frequency spectrum is illustrated by a Dynamic Spectrum Access (DSA) system that includes multiple base stations/networks that operate independent of one another to share an allocated frequency spectrum. A DSA system typically includes an incumbent frequency spectrum user that has highest priority for spectrum access. A DSA system is typically configured so that the base stations/networks within the DSA system use channels in a frequency spectrum that is shared with other base stations/networks of the DSA system. The sharing of the frequency spectrum in the DSA system may be done under the coordination of a controller that manages a channel assignment database. Various groups in the wireless industry are currently working to standardize operating rules for DSA systems that have multiple tier levels of priority for spectrum access. In these systems, each base station/network in the DSA system may be assigned one of the multiple tier levels of priority. A DSA database system enabling multiple tier levels of priority is commonly known as a spectrum access system (SAS).